Ecological subsidies and ecosystem function: the role of dislodged seaweeds in the energy flow between coastal habitats

生态补贴和生态系统功能：被驱逐的海藻在沿海生境之间能量流中的作用

• 批准号: RGPIN-2017-05581
• 负责人: Johnson, Ladd
• 金额: $ 2.04万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711475
• 关键词: Ecological; subsidies; ecosystem; function; role

Ecosystems can be connected by the flow of energy and material between them a form of ecological subsidy between donor and recipient areas. In marine coastal zones, habitats ranging from highly productive areas (e.g., rocky shores, salt marshes) to ones with extremely low productivity (e.g., sandy beaches, mud flats) form an interconnected mosaic with energy transferred by the transport of dislodged plants (e.g., seaweeds, marsh grass) by coastal currents. Typically waves, especially those occurring during storms, are the disturbance agents responsible for dislodging plants, but at higher latitudes scouring by sea ice can be equally or even more important. This added ecological factor can alter the dynamics of the process of ecological subsidies with possible consequences for the higher trophic levels that depend on this resource. Although such subsidies have been well recognized and frequently observed in coastal ecosystems, the variation in the temporal and spatial dynamics over which this energy transfer occurs remains largely undocumented. Moreover, the role of disturbance from ice scouring is entirely unknown. Preliminary work in the St. Lawrence maritime estuary has, however, shown a dramatic shift in the timing of the accumulation of dislodged seaweeds on the shore (known as “wrack”) with the dominant pulse occurring in the spring. The general objective of this proposal is to determine the spatio-temporal dynamics of this ecological subsidy, including specific objectives that assess (1) the local seaweed production in source areas and the contrasting disturbance processes dislodging seaweeds; (2) the transport of dislodged seaweeds from these sources areas and their accumulation in sink areas; and (3) the impacts on animal assemblages (e.g., invertebrates, birds) exploiting this resource. The first aspect of this study will be addressed using time series that map seaweed beds in tandem with high-resolution measures of wave forces and ice scouring within the beds. The second aspect will be explored first using the particle-tracking capacities of existing circulation models to predict the likely connections between source and sink areas, and then by the release and recovery of drift cards to empirically validate the model's predictions. The final aspect will be investigated by descriptive and experimental work aimed at documenting the patterns of the deposition of seaweed wrack and manipulating its abundance to determine how the spatial and temporal availability of wrack influences the population dynamics of the detritivores (i.e., invertebrates such as insects, worms, crustaceans) and the predators (e.g., spiders and birds) that depend on this resource. Overall, the proposed research will provide a cradle-to-grave perspective that will allow us to predict how subsidies will respond to environmental change, especially climate-induced changes to sea ice dynamics.

生态系统可以通过它们之间的能量和物质流动连接起来，这是捐助区和受援区之间的生态补贴形式。在海洋沿海地区，栖息地范围从高生产力地区（例如岩石海岸、盐沼）到生产力极低的地区。 （例如沙滩、泥滩）形成相互连接的马赛克，通过沿海水流（尤其是波浪）移动的植物（例如海藻、沼泽草）传输能量。风暴期间发生的那些是导致植物移动的干扰因素，但在高纬度地区，海冰的冲刷可能同样重要甚至更重要，这种额外的生态因素可以改变生态补贴过程的动态，并可能对更高的地区产生影响。取决于该资源的营养级。 尽管这种补贴在沿海生态系统中已得到广泛认可并经常观察到，但这种能量转移发生的时间和空间动态的变化在很大程度上仍然没有记录。此外，圣路易斯地区的初步工作完全未知。然而，圣劳伦斯河口的岸边海藻堆积（称为“残骸”）的时间发生了巨大变化，主要脉冲发生在春季。 该提案的总体目标是确定该生态补贴的时空动态，包括评估以下具体目标：(1) 源区当地海藻生产以及驱逐海藻的对比干扰过程；(2) 驱逐海藻的运输；来自这些源区及其在汇区的积累；(3) 对利用该资源的动物群落（例如无脊椎动物、鸟类）的影响。这项研究将使用时间序列来绘制海藻床，并结合海藻床内波浪力和冰冲刷的高分辨率测量结果来解决。第二个方面将首先利用现有环流模型的粒子跟踪能力来预测可能的情况。最后一个方面将通过旨在记录海藻残骸沉积模式并操纵其丰度的描述性和实验性工作进行研究。确定残骸的空间和时间可用性如何影响依赖于该资源的食碎物动物（即无脊椎动物，如昆虫、蠕虫、甲壳类动物）和捕食者（例如蜘蛛和鸟类）。将提供一个从摇篮到坟墓的视角，使我们能够预测补贴将如何应对环境变化，特别是气候引起的海冰动态变化。